I think I roasted my 1-2 clutches in my 700r4 as I'm getting a ton of slippage above 3000rpms. I guess this could also be the tq but it pulls like a monster in 3rd and 4th gears. Just looking for some pity here.

Also, I'm currently running a 2400 stall converter and am wondering if this is too low. How do you "scientifically" know what to stall speed is best? Here are some specs...

- 10.5:1 comp
- Hyd roller .5 lift w/ 1.6 rockers on top of that
- 3.36 rear gears

Big stall numbers scare me as my engine is really a low end torque motor. It makes power to about 5500rpm. I think putting too big a stall speed will do more damage than good. Any help appreciated...

--Jack

 

You "scientifically" write checks to buy and try different converters. Every car is different and accepts changes differently. Even the most knowledgeable converter expert's recommendation is only an educated giess.

I can give you the benefit of my experience. I have a well tuned but mostly stock Crossfire. The only engine modification is a home ported factory Crossfire intake manifold. Years ago, before I started racing and playing with the car, the trans went. I have reason to believe the trans shop installed a tighter than (Corvette) stock converter. I really didn't notice a difference, until I started racing, and noticed I couldn't brake torque beyond 1200 rpms before it over powered the brakes. Transmission number 2 went south, after yeoman duty, and I had one "built to the hilt", in anticipation of a new engine. They installed a Vigilanti 2600 stall converter. My 60's dropped 3-4 tenths. My ETs dropped 6-7 tenths. I have a feeling I could use more converter. 3000 rpms, maybe? Unfortunately, only money will tell. The Crossfire is a torque engine. The peak is at 2900, stock. My manifold may have raised that slightly. My guess is that you make more torque and make it at a higher rpm than I do. I wouldn't be afraid of a 3000-3200 converter, if I were you. Good luck, and...

RACE ON!!!

 

high end lockup converters like the vigilanty 9.5 inch has very little slip when cruising and the motor is not loaded. So in my case on a level freeway at 80 mph fourth gear and I hit my manual lockup taggle switch the rpm only drops 200-300 rpm and that's with a 3500 stall

On my older 355 ci motors I went as high as a 3800 10 inch.

IMO - you really need a 3.90 - 4.11 rear to really used OD tranny's

 

Well here's something I didn't know...

Stall speed listings are based on engines producing 230lb. ft. of torque at 2,500 rpm. More torque at 2,500 rpm will give you more stall speed, less torque at 2,500 rpm will give you less stall speed than the stall speed ratings indicated.

... thats from the B&M website.

 

When you buy the efficient converters from the high end companies. The will have you fill out a questioneer form of engine mods etc.

So if you ask for a 3500 stall with 500 lbs of TQ that what you get.

B&M or TCI are not high end companies. Be prepaired to spend $800 up for quality units.

 

What makes one converter good and another not so good? Why Vigilante, not B&M or TCI?

 

What makes one converter good and another not so good? Why Vigilante, not B&M or TCI?

You really have to cut the converters in half and then you can see why!

I had a place cut one of my failed units apart. It was a $500 B&M or something like that. The shock of running a transbrake had shatered the aluminum stator (I hope that I'm using the correct part name?) The stator is splined onto the main shaft which transmits all the power on out to your rear tires. When it broke and got eaten up by all those nice furnace brazed fins, it then sent ground aluminum all through the tranny and cooler. This particular tranny was supposed to be a high power unit with 8 or so folded springs and weights designed to absorb high stall and transbrake shock.

I really believe that you get what you pay for!



It was an expensive mistake to go with the low bidder. I have friends who have Continental Converters behind 1200 and 2000+ hp Nastalgia drag cars and they say my Art Carr Racing $1100 converter is cheap.

The difference between the $800+ dollar unit and the B&M or TCI is: How familiar do you want to get with R&R of your tranny and the TC. Do you want to make hundred of passes down the strip in sub 12 seconds capable cars or just make maybe half of one 1/4 mile pass.


[Modified by gkull, 12:30 PM 6/23/2004]

 

Thanks for your reply. Good to know, I thought it is the last part to broke in a driveline. I need to keep this info in mind when I start stroking my engine.

Thanks!

 

I personally don't like a loose or high stall convertor for the street. I guess it depends on what you want out of it. The best 60' time? I use a 2400 stall behind my LT1 and have no problem frying the tires. I can even spin my drag radials pretty bad at the track if I flash the convertor. I like the 2400, but my car is not a dedicated "drag" car. It suites me.. As for your tranny, if second gear slips, I am suprised that 4th doesn't. They use the same band. Maybe a valve is stuck in there or something.

 

My BTO level 3 went south after just one 6500 rpm run. I had a local rebuilder "fix" it due to a warranty dispute.He ,to my surprise, reused the 2200 rpm stall converter supplied by BTO(flushed out I guess) and insisted high stalls would only hurt a street driven transmission.I was looking into Vigilante's in the 2800 rpm range,but saved a pile of money by reusing what I had. I have to be honest with you, the 2200 works,and I have no problem roasting 10" wide tires off the line or even from a 30 mph roll. I'm not sure how you'd ever hook up with a higher stall converter.

I do not drag race,so every millisecond shaved off the ET means nothing.A friend of mine was following me home one day and as I pulled out onto the highway,I goosed it,and within seconds was passing cars already moving at 65-70 mph.He told me the next day it looked like my car was being shot out of a cannon. Good enough for me.